Excitatory and inhibitory amino-acidergic determinants of the pressure-induced neuronal hyperexcitability in rat hippocampal slices.
In a previous study we found that the intrinsic excitability of the hippocampal CA1 pyramidal cells increased under helium pressure (80 bar). We presently show that drugs inhibiting gamma-aminobutyric acid (GABA) uptake or facilitating GABA binding partially reversed the pressure-induced hyperexcitability of the CA1 pyramidal cells. When these drugs were simultaneously applied with 2-D,L-aminophosphonovaleric acid, a specific antagonist of N-methyl-D-aspartate (NMDA) receptors, the effect of pressure on the neuronal excitability was nearly abolished. These results suggested that the observed pressure-induced hyperexcitability of pyramidal cells resulted from reduced efficiency of GABA transmission and facilitated excitation mediated by NMDA receptors.
Zinebi
F
F
CNRS-URA 1330, Faculté de Médecine Nord, Marseille, France.
Fagni
L
L
Hugon
M
M
D000818:Animals; D003975:Diazepam / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009557:Nipecotic Acids / Q000494:pharmacology; D011312:Pressure; D011392:Proline / Q000031:analogs & derivatives*; D011712:Pyramidal Tracts / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D013451:Sulfonic Acids / Q000494:pharmacology; D014631:Valerates / Q000494:pharmacology
D009557:Nipecotic Acids; D013451:Sulfonic Acids; D014631:Valerates; C030278:nipecotic acid; D011392:Proline; C010983:homoproline; D003975:Diazepam